Self-lowering screw jack



J. C. KOPF.

SELF LOWERING scnsw JACK. APPLICATION FILED AUG-2, i920.

1,41 1,282. Patented Apr- 4, 1922.

5 SHEETS-SHEET I- 12 I 5 I 13 i I 1 4 INVENTOR.

1. c. KQPF.

SELF LOWERING SCREW JACK.

APPLICATION FILED AUG.2, I920.

1,41 1,282. Patented A r. 4, 1922.

5 SHEETS-SHEET 2.

v 1 ENTOR.

.7 HEY%C' Q J. C. KOPF.

SELF LOWERING SCREW JACK.

APPLICATION FILED AUG-2| 920.

1 ,41 1,282. Patented Apr. 4, 1922.

5 $HEETS-SHEET 3.

. ATTORNEY 1. 'c. KOPF,

SEL-F LOWEBING SCREW JACK.

APPLICATION FILED Auc.2. 1920.

1,411,282. Patented Apr. 4, 1922.

5 SHEETS-SHEET 4- INVENTOR.

J. C. KOPF.

SELFYLOWERING SCREW JACK.

APPLICATION FILED AUG.2, I920.

Patented Apr. 4, 1922.

5 SHEETSSHEET 5.

l N VEN TOR. w c 74 UNITED STATES 1 Joinio. Kor'r, or BELLEVUE, PENNSYLVANIA, ASSIGNOR To THE. DUFF MANUFAC- TURINGYCOMPANY, or PITTSBURGH, PENNSYLVANIA, A CORPORATION or PENN- SYLVANIA;

To allwhom z'tmay concern: a

Be it known that I, JOHN C. Kori, a citizen of the United States, and resident. of .the borough of. Bellevue, in the county of ingscrews beyond the angle of repose, and

mechanism connected therewithwhereby the -.1'oaded jacking member can be-allowed to run down under the control of braking means. Such jacks as heretofore. constructed have involved more orless complication of mech- -anism,,because of the elementof danger in lowering'heavy loads'in this manner; which- I In the accompanying drawlngs illustratinechanism has almost-universally been car- 20;

ried in an enlarged head of the vertically movable jacking member, the jack as a whole thus being cumbersome and topheavy and liableto bending of its=screwby canted load. aThe object of the present invention is to provide a self-lowering jack which shall be safe, simple, stable,-convenient to handle and operate and inherently protected by its .mechanism and generalorganization againstinjury, both from improper acking and the vicissitudes of lowering.

ing the invention {-F'gure 1. 's a rear elevation ofa jack em- -bodying the invention, the outer portion of theliftin shaft being sectioned; Fig. 2 is a vertical section taken in the plane of'the axes of the lifting screw and lifting shaft, which members are seen 1n elevation;

Fig. 3 is an enlarged vertical section on the line 3-3 of Fig. 2;

- .Fig; 4 is an enlarged vertlcal section on the line 44: of Fig. 1;

Fig. 5 is an enlarged perspective view of Fig.7 is an enlarged front elevation of the drum; 7 V Fig. 8 is an enlarged'view of the drum partly in side elevation and partly in section and F igsq9 and 10 are enlarged perspective views of two of the disks.

PATENT OFFICE.

SELFI-LOWERING SCREW JACK.

Application filed August 2,1020. Serial No. 400,801.

. A cylindrical ram 4 having a small head?) is contained withinthe standard in the lowered condition, and has slidable bearing in a rigid guide 6 in the top of the standard.

I Specification of Letters Patent. Patented xp'n 4 1922,

The ram is also hollow'to accommodate the vertical steep-pitch screw -7, which is supported by a ball-bearing 8 upon the top of the base proper. The vertically-movable ram or acking member is held against turning by akey'9: in the upper portion of the; 7 standard cooperating with a, vertical groove I.

10 in the ram,.and atits lower end the ram has a nut 11 to. cooperate withuthe screw.

A horizontal main operating shaft, 12 is ing with a bevel gear 16 keyed to the lower portion of the screw. A worm wheel 17 is journaled in a bearing, 13-in the outer wall V 14 of the annex 3., and is geared to the screw I by a bevel pinion 15- 011 its inner end mesh- 7-5 fixed by a key 18 to the operating shaft, be

same and the inner end of the bearing 13, which projects for a substantial distance within the annex- Said worm wheel meshes hind the bevel. pinion 15 and, between the with a worm 19 on a sh'aft20, the'axis or shaft of the worm being transverse to the 4 main operating shaft 12. The shaft 12, the

outer portion of which will beiunderstood to be formed for operation by the usual lever and pawl rocker, may be termed thelift- I.

ing shaft, and the worm, or' its axis, the holding and lowering shaft. I The worm and worm-wheel are of sufiiciently steep pitch,

so that, like the screw, they will run down by gravity under theaction of the load, the A worm-wheel driving the worm. A portion of the action ofthe load which is transmitted tothe worm produces an end-thrust therein, which acts toward the left in Fig. 3 of the drawings. To hold and release the worm, and therefore ;the jacking member, means are provided which will. now be described.

In the particular construction illustrated,

the worm 19 andparts associated upon its. axis are housed ma transverse chamber 21 merging with the top of the annex and the back of the standard, and having its outer portion 22 enlarged to form a brake-chambel'. Said brake-chamber has a large'circular entrance 23 at the outer end, which is closed by a bolted-0n cover-plate 22, having a circular alining shoulder 24 fittlng the entrance. In the center of this cover; plate,

and in the remote end wall of the chamber 21, are journal bearings 25, 26 for the journal ends of the worm shaft 20. On said shaft, between the worm and the inwardly projecting bearing 25 of the cover-plate, is a collection of fiat, smooth faced friction disks 27, 28, of which the set 27, is coupled-to the worm-shaft for rotation therewith, while the set 28, in this particular instance, 1s engaged with a drum 29. Thus positioned, the pile of friction elements is adapted to be compacted and locked by the end-thrust of j the worm under load. The combined friction 0f the surfaces is such as to insure safe holding under any conditions, but need not be excessive, since the pressure producing locking is automatically adjusted to the load. With such a device there is-a desirable mo- 'mentary cushion slippage when arresting -the momentum of lowering.

"respect to rotation, with capacity for slight :The disks 27 are coupled'to the shaft in "longitudinal movement thereon, by means of llongitudinal ribs or integral splines 30 'pinched outjof'an intermediate portion of so 7 7 "sides of the central holes 32 whereby the the shaft, and cooperating notches 31 at the disks arestrung upon the'shaft. The disks '28 have larger central openings '33 permitting the shaft to turn therein, and are of 35 "so that they may be formed-with external,

larger-outside diameter than the disks 27,

notches .34'for engagement with internal longitudinalribs 35 on the sides of the drum 29." Y

Theend-thrust of the worm is exerted upon thedisks through a collar or spacer 36, and isfsolidly sustained by the bearing front of the ribs 85.

in the collar are provided to accommodate with the latter. is further provided with a central bearing 25." The drum has a back wall 37, which is interposed between "the disks and the end abutment of the bearing 25, and formed with an end-thrust bearing boss 38 for contact The said wall of the'drum opening 39 whereby it is supported on a smooth portion of the shaft, in addition to which the open forward part of the drum has relative rotary bearing on a circular flange 40 on the thrust-collar 36, the entrance of the drum being formed for this purpose with a large-diameter bearing 41 in Internal grooves 42 the shaft ribs 30.

The drum is encircled by a brake-band 48,

with friction lining 44, by which the drum is held against rotation in order to sustain the load, or released for lowering. The brake-band has reinforced end members 45 provided with perforations 46; and a spring 47 interposed between these members tends to release the brake from the drum. The brake is supported by a rod '48, whichextends from a screw 49 across the top of the brake chamber, through the perforated end I members and the spring, into a bearingaperture 50 in the inner side wall of. the chamber. The said screw occupies an internally screw-threaded opening 51 in the outer. side carries a crank-handle 52, by manipulation of which the operator effects lowering of the load. Thus, a partialturning movement of the handle in one direction causes the inner end of its screw to press upon the adjacent end member 45 sufficiently to clamp the brake-band upon the drum, while similar 'tion 53 and a standardsection 54, with the annex 3 integral with the lower part of the .wall of the chamber, and at its outer end a standard section and its outer wall-14"con- V stituted as a "removable cover-plate. The

sections 53 and 54 have circular interfitting alining formations 55, 56 on their, meeting parts, and areunited by bolts 57 and the rear opening of the annex ismadecircular to receive a circular alining shoulder 58 on the cover-plate, which issecured by bolts 59.

The operation will be briefly 'stated. Lift -v -ing is performed by ratcheting the main shaft in the ordinary manner. At such time the brake 43 holds'the drum 29 and 'conse quently the disks 28 against rotation. During each liftingstrokethe end-thrust pressure of the worm is removed from the collection of disks, so that the'disks 27i can turnfreely; but as soon as the effort ceases the load tending to cause the jacking member to sink back mews the worm 'endwise slightly and 're-applies the pressure to the look, so that the disks 27 are held against rotationby the frictional embrace of the disks 28, with the result that the load is antomatically held. To lower, the operator moves the handle 52 so as to remove'the brake and permit theentire assemblage of disks and the drum to turn, with the worm,

so that the jack'runs down by gravity. By

manipulation of the handle the operator controls the lowering, checking and stopping of the load, this manual. regulation being the more effective because of the manner of supporting and operating thebrake. In case of the brake being applied suddenly, the heavy momentum isnot instantaneously arrested with destructive effects, because of the property of the plane surfaces of the disk elements for relative slinpage'under such circumstances. Such yielding, it will be understood, is brief, because the load thrust of the worm is always sufficient for holding, but it is enough to save the mechanism from breakage. Slipping practically does not occur at the conclusion of the lifting strokes because the parts do not gather momentum, and the sink-back at suchtime need i be no greater, and can be less, ,than that in the ordinary ack mechanisms,

' The construction, it will be observed, is very simple and compact, as well as efficient, the'entire hOlding and self-lowering mechanism being on a single shaft or axis in the base, geared to the main lifting shaft. The hroad'base, stationarily supporting the operating" and controlling mechanism, the location of which confers a permanent low center of gravity and working fulcrum, and

, the small-head ram guided in the top of the standard, together insure stability and compel jacking substantially in linewith the main screw, and produce a jack which is advantageous for moving about and for transportation on the railroads.

The jack hereof will be perceived tobear a specificrelation to the generic invention of the Kopf and Schwerin Patent vNo; 1,329,665 ofFebruary-3, 1920, and to that b of my prior Patent No. 1,321,456, dated November 11, 1919. I'do not necessarily limit myself to the .particular embodiment and mode of control of the multiple disk device, as in a.copending application I have disclosed another construction in which the restraining disks are'-perma-' pitch lifting screw rotatably supported on the base and extendin u wardwithin the ram, a horizontal lifting shaft in the base.

geared, to the lower part of the screw, a-wormwheel on said lifting shaft, a second shaft in the base bearing a worm meshing said wormwheel and of such pitch asJto *be driven thereby, andv holding and releasing means applied to said second shaft. 1

2. A self-lowering jack comprising a base with a hollow standard rising therefrom, a ram slidably guided in the standard, a steep-pitch lifting screw rotatably supported on the base and extending upward-within the ram, a horizontal lifting shaft in the base geared to the lower part of the screw, a worm-wheel on said lifting shaft, a second shaft in the base bearing a worm meshing said worm-wheel and of such pitch as tobe driven thereby, a multiple friction disk device on' said second shaft subject to the endthrust of its worm under load, and means for controlling said device.

3. A self-lowering jack comprising a base bly supported onthe base and extending upward. within the ram, a main shaft in the annex geared to the lower part of the screw, means for operating said shaft to lift the load, a worm-wheel on said shaft, a second shaft in said annex transverse to the main shaft and bearing a worm of a pitch to be driven by said worm-wheel, a holding and releasing device on said second shaft in the upper. part of the base annex, and a lowering control handle on the annex connected to said device.

i. A self-lowering jack having an 'enclosing supporting frame comprising a base section, a separate standard section, an annex integralwith'the standard section and having a circular rear mouth, and a cover plate having a circular shoulder fitting said mouth and an inwardly projecting bearing, in combination with a ram slidably guided in the standard section, a steep-pitch screw rotatably supported on the base section andextending upward within the ram, a bevel ear on the lower part of the screw, a horizontal lifting shaft journaled in the hearing of said cover plate and carrying a bevel pinion on its inner end meshing the gear on the screw, a worm-wheel on the lifting shaft between said pinion and bearing, a second shaft journaled in the annex, a steep-pitch worm on said second shaft meshingfthe worm-wheel, and means for holding and releasing the worm.

5. In a self-lowering jack, a jacking member and mechanism adapted to run down underthe load, including a worm-wheel in driven relation to the jacking member said bearinganda brake-chamber behind said entrance, a cover plate for said entrance containing the other bearing for the worm-shaft, a multiple disk device on the wormshaft within said brake-chamber, and a brake encircling said device.

6. In a self-lowering jack, the combination with a holding and lowering shaft and a steep-pitch worm thereon, of multipledisk means comprising disks engaged with the shaft and disks alternating therewith, and a barrel wherewith the latter disks are engaged, an abutment,said barrel having a back formed with a central bearing opening and sustained against said abutment, and a thrust collar interposed between the worm and the disks and having a circular bearing cooperating with the open side of the barrel.

7. In a self-lowering jack, and in combination with a jacking member and mechanism adapted to run down under the load, means for holding and releasing the mechanism including a drum connected therewith,

a brake-hand encircling the drum and having perforated end members, a frame hav-- ing an internally screw-threaded opening, a crew in sald openlngforcompressing the band and a rod extending across through down under the load, an enclosure having a' said end members, and resilient means for releasing the band.

V 8. In a self-lowering jack, having a jacking member and mechanism adapted to run screw-threaded opening in its wall, holding and lowering means in said enclosure including a drum and a brake-band, a control screw in said threaded opening cooperating at its inner end'with the brakeband, and ahandle on the outer end of said screw.

9. A self-lowering jack comprising a'base with a hollow standard rising therefrom, a

ram slidabl'y guided in thestandard, a steeppitch lifting screw rotatablys'upported on the base and extending upward "within the ram, a horizontal lifting shaft in the base gearedto the lower part of the screw, a second shaft in the base, meshing gears on the lifting shaft and onv said second shaft" JoHN o. Kora 

